From Wikipedia, the free encyclopedia

Rubble is broken stone, of irregular size,shape and
texture. This word is closely connected in derivation with "rubbish",
which was formerly also applied to what we now call "rubble".
Rubble naturally found in the soil is known also as
'brash' (compare cornbrash). Where present, it becomes more
noticeable when the land is ploughed.

Building

"Rubble-work" is a name applied to several species of masonry. One kind, where the
stones are loosely thrown together in a wall between boards and grouted with mortar almost
like concrete, is called
in Italian
"muraglia di getto" and in French "bocage". In Pakistan, walls
made of rubble and concrete, cast in a formwork, are called 'situ',
a word which probably derives from the Latin 'in situ' meaning
'made on the spot'.

Work executed with more or less large stones put together
without any attempt at courses is called rubble walling. Where
similar work is laid in courses, it is known as coursed rubble. Dry-stone walling is somewhat similar work
done without the use of mortar. It is bound together by the fit of
the stones and the regular placement of stones which extend through
the thickness of the wall. A rubble wall built with mortar will be
stronger if assembled in this way.

Rubble Walls - In Malta Rubble walls are found all over the
island. Similar walls are also frequently found in Sicily and the
Arab countries. The various shapes and sizes of the stones used to
build these walls look like stones that were found in the area
lying on the ground or in the soil. It is most probable that the
practice of building these walls around the field was inspired by
the Arabs during their rule in Malta, as in Sicily who were also
ruled by the Arabs around the same period. The Maltese farmer found
that the technique of these walls was very useful especially during
an epic where resources were limited. Rubble walls are used to
serve as borders between the property of one farm from the other. A
great advantage that rubble walls offered is the fact that when
heavy rain fall their structure would allow excessive water to pass
through and therefore, excess water will not ruin the products. It
is also a known fact that water carries with it anything in its
path including the soil in the field, however the wall structure
allows the water to pass through but it traps the soil and it will
prevented it from being carried away from the field. One can view
frequent rubble walls on the side of the hills and in valleys where
the land slops down and consequently the soil is in greater danger
of being carried away. The following web site gives you an image of
a rubble wall. http://www.searchmalta.com/cgi-local/photos/main.cgi?id=3398&type=3&brand=0